Method of restoring hydraulic systems

Abstract

A method of cleaning and replenishing vehicle hydraulic brake systems is provided which includes opening all of the bleeder screws at the outlet end of the brake system and allowing the old brake fluid to flow from the brake system. Liquid solvent dichlorodifluromethane is then injected into the brake system under pressure at the master cylinder and allowed to flow through the system and out the bleeder screws. As the solvent enters the brake system, it wil mix with any remaining brake fluid and water in the system and, upon vaporization, will remove the remaining brake fluid and water from the system. When the solvent is observed flowing out of the bleeder screws, the solvent is shut off at the master cylinder and the bleeder screws are closed. A vacuum is then applied to the brake system at the master cylinder to vaporize and remove any solvent trapped in the system and to remove all air from the system. While the vacuum is maintained, new brake fluid is injected under pressure into the brake system through the master cylinder until the brake system is filled with new brake fluid. The connection to the master cylinder is then removed and the hydraulic brake system is closed.

What is claimed: 
     
       1. A method of cleaning and replenishing a hydraulic system having first and second ends, comprising the sequential steps of: opening the ends of the system to allow hydraulic fluid in the system to drain from the system;   injecting an organic solvent into the system through one end of the system and out the other end of the system, said solvent being miscible with oil and water and vaporizable at low temperatures and at atmospheric pressure;   terminating the flow of solvent and closing the first end of the system;   applying a vacuum to the second end of the system to vaporize the solvent and remove the solvent vapor and air;   injecting hydraulic fluid into the second end of the evacuated system to fill the system with hydraulic fluid while the vacuum is maintained on the system; and,   closing the second end of the system.   
     
     
       2. The method of cleaning and replenishing a hydraulic system as defined in claim 1, wherein said hydraulic system is a vehicle brake system, said hydraulic fluid is brake fluid, and said solvent is dichlorodifluromethane. 
     
     
       3. The method of cleaning and replenishing a hydraulic system as defined in claim 2, wherein said organic solvent is injected into the system as a liquid under pressure. 
     
     
       4. A method of cleaning and replenishing a vehicle hydraulic brake system having first and second ends, comprising the sequential steps of: opening the ends of the system to drain hydraulic brake fluid from the system;   injecting dichlorodifluromethane solvent into the brake system through the first end of the system and out the second end of the system;   closing the second end of the system;   vaporizing the solvent;   applying a vacuum to the first end of the system to remove air and solvent vapor from the system;   injecting hydraulic brake fluid into the first end of the system to fill the system with hydraulic brake fluid while the vacuum is maintained on the system; and,   sealing the system.